Bismuth oxide (Bi2O3) is a metal oxide that has unusually high ionic conductivity due to the high mobility of oxygen atoms through the structure. Additionally, bismuth oxide is transparent with a high refractive index (between about 2.3 and about 2.5) depending on its different phases. Therefore, it may have potential uses in applications such as solid oxide fuel cells (SOFC), batteries, electrochromic devices, solar cells, display devices, etc. wherein the Bi2O3 films are commonly deposited directly on a substrate. The Low-emissivity glass needs a high refractive index oxide, where Bi2O3 could be a candidate due to its high refractive index. However, typically, a temperature treatment (such as above 600 C.) at a short time (such as 8 min) is required in this low emissivity application, although there is no need for this heat treatment for many other Bi2O3 applications. However, impurities from the substrate could diffuse into the bismuth oxide. At room temperature, a small amount of impurity may diffuse into the bismuth oxide. At higher temperatures, a significant amount of impurity may diffuse into the bismuth oxide. These impurities may negatively impact the performance of the Bi2O3 layer, depending on the amount of impurity and the required specification of the various applications. As an example, when materials containing Si, alkali, or alkaline earth metals glass are used as the substrate, impurities such as Na, Ca, Si, etc. can easily diffuse out of the substrate and into the bismuth oxide. These impurities impact both the optical and ionic conducting properties of the film. Therefore, there is a need to develop methods for preventing the diffusion of impurities into the bismuth oxide for deposition on glass or substrates containing Si, alkali metals, or alkaline earth metals with a subsequent process involving higher temperatures, and using only transparent materials for the low-emissivity applications.